Projector

ABSTRACT

A projector includes a projection lens having a plurality of lenses and projects modulated light from a light modulator, a receiver that externally receives an optical signal, and an exterior enclosure that forms the exterior of the projector. The projection lens has a front-side lens disposed in a most downstream position in an optical path among the plurality of lenses and having a diameter larger than the diameters of the other lenses. The exterior enclosure has an upper surface portion. The upper surface portion has a swelling portion that swells in such a way that the swelling portion covers part of a circumferential edge portion of the front-side lens. The receiver is disposed in the swelling portion and so oriented that the receiver receives the optical signal incident from a side opposite to a side where the light is projected through the projection lens.

BACKGROUND

1. Technical Field

The present invention relates to a projector.

2. Related Art

There is a known projector of related art that modulates light emittedfrom a light source in accordance with image information and projectsthe modulated light on a screen or any other projection surface.Further, a projector is provided with an input terminal and othercomponents to be connected to an external apparatus, and there is aproposed projector including a cover member that covers the inputterminal, a cable connected to the input terminal, and other componentsso that exterior appearance is improved and no dust or dirt attaches tothe input terminal and other components (see JP-A-2004-207400, forexample).

The cover member described in JP-A-2004-207400 (cover for electronicapparatus enclosure) has a cover body formed in a roughly box-likeshape. The cover body has a cover upper surface portion, a cover sidesurface portion, a cover rear surface portion, and a cover bottomsurface portion. The cover upper surface portion has a protrudingportion formed in a roughly central portion in the width direction, andthe protruding portion protrudes upward. A ridgeline portion where thecover upper surface portion and the cover side surface portion intersecteach other has a recessed portion formed therein, and the recessedportion concavely retracts along the ridgeline. The recessed portion isformed in correspondence with a light receiver provided on the rearsurface side of the projector, and the light receiver is capable ofreceiving an operation signal from an external remote control even whenthe cover member is attached to the projector.

However, in the projector described in JP-A-2004-207400, in which thecover member is provided with the protruding portion and the recessedportion, a step is created in a portion between an exterior case and thecover member and does not necessarily provide a good exteriorappearance. Further, since a portion for forming the recessed portion ofthe cover member comes into contact with the rear surface of theexterior case, no connection terminal or other components canundesirably be disposed in the portion.

To avoid the problem described above, in a case where the step betweenthe exterior case and the cover member is shortened and a holecorresponding to the light receiver is formed in the cover member, thehole needs to be large in consideration of the directivity of the lightreceiver, resulting in poor exterior appearance, and it is conceivablethat the function of the cover member is compromised because dustreadily enters externally. It is instead conceivable to insert a lighttransmissible member that transmits an external optical signal into thehole. This approach, however, increases the number of parts and makes itdifficult to improve exterior appearance because the cover member andthe light transmissible member differ from each other in terms of colorand texture.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the problems described above, and the invention can beimplemented as the following aspects or application examples.

Application Example 1

A projector according to this application example is a projectorincluding a light source, a light modulator that modulates light emittedfrom the light source in accordance with image information, a projectionlens having a plurality of lenses and projects the modulated light fromthe light modulator, a receiver that externally receives an opticalsignal and outputs an electric signal according to the received opticalsignal, and an exterior enclosure that forms the exterior of theprojector. The projection lens has a front-side lens disposed in a mostdownstream position in an optical path among the plurality of lenses andhaving a diameter larger than the diameters of the other lenses. Theexterior enclosure has an upper surface portion that faces upward in astanding attitude of the projector. The upper surface portion has aswelling portion that swells in such a way that the swelling portioncovers part of a circumferential edge portion of the front-side lens.The receiver is disposed in the swelling portion and so oriented thatthe receiver receives the optical signal incident from a side oppositeto a side where the light is projected through the projection lens.

According to the thus configured projector, the upper surface portion ofthe exterior enclosure is provided with the swelling portion, whichswells in such a way that it covers part of the circumferential edgeportion of the front-side lens, and the receiver is disposed in theswelling portion and so oriented that the receiver receives an opticalsignal incident from the side opposite to the side where the projectionlens performs projection. That is, assuming that the side where theprojection lens performs projection is the front side, the receiver isso disposed that it receives an optical signal transmitted from aposition behind the projector. As a result, even in a configuration inwhich an input terminal and other components are provided on the rearsurface of the projector and a cable cover that covers a cable connectedto the input terminal and other components is attached to the rearsurface of the projector, the cable cover does not block an opticalsignal directed from the rear surface side toward the receiver. Theprojector therefore allows the receiver to reliably receive an opticalsignal transmitted from the rear surface side and can perform action orimage projecting according to the received signal without providing thecable cover with a special shape (such as hole or recess) for opticalsignal reception or without configuring the cable cover by using amember that transmits an optical signal. Further, since the receiver isdisposed with the aid of the swelling portion formed in correspondencewith the front-side lens, the receiver can be disposed withoutdegradation in the exterior appearance of the projector.

Application Example 2

In the projector according to the application example described above,it is preferable that the receiver is so inclined that a central axis ofan area over which the receiver has a directional characteristicseparates away from the projector by a greater distance as the centralaxis extends farther away from the swelling portion toward the oppositeside.

According to the configuration described above, since the receiver is sodisposed that it is inclined as described above, in an attitude in whichthe projector is installed on a desktop or any other surface (standingattitude), the receiver can receive an optical signal issued from anobliquely upward position behind the projector and positionstherearound, whereas in an attitude in which the projector is installedon a ceiling or any other surface or in an upside-down attitude (hungattitude) instead of the standing attitude, the receiver can receive anoptical signal issued from an obliquely downward position behind theprojector and positions therearound.

Application Example 3

In the projector according to the application example described above,it is preferable that the receiver is attached to the projection lens.

According to the configuration described above, since the receiver isattached to the projection lens, the receiver and the projection lenscan be manufactured integrally with each other and then disposed in theexterior enclosure. The projector can therefore be manufactured in asimplified manner.

Application Example 4

In the projector according to the application example described above,it is preferable that the projection lens is provided with a leverlocated on the side opposite to the swelling portion and used for atleast one of focus adjustment and zoom adjustment, and the lever islocated in a position outside a predetermined area containing a positionin the directional characteristic area of the receiver where receptionsensitivity is maximized.

According to the configuration described above, since the lever does notblock an optical signal directed toward the area where the receiver hashigh reception sensitivity, the receiver can reliably receive an opticalsignal from the rear surface side even when focus adjustment or zoomadjustment is performed.

Application Example 5

In the projector according to the application example described above,it is preferable that the receiver preferably receives an optical signalissued from a remote control used to remotely operate the projector.

According to the configuration described above, the projector can bereliably remotely controlled through operation of the remote controlperformed by an image viewer who is present behind the rear surface ofthe projector even when the cable cover is attached to the rear surfaceof the projector.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is an exterior view of a projector according to an embodiment ofthe invention viewed from a projection surface side.

FIG. 2 is an exterior view of the projector according to the embodimentviewed from the side facing the projection surface.

FIG. 3 is a diagrammatic view showing a schematic internal configurationof the projector according to the embodiment.

FIG. 4 is a perspective view showing a projection lens and a receiver inthe embodiment.

FIG. 5 is a cross-sectional view of part of the projector in thevicinity of a swelling portion in the embodiment.

FIG. 6 shows the projector to which a cable cover in the embodiment isattached and a remote control located behind the projector.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A projector according to an embodiment of the invention will bedescribed below with reference to the drawings.

The projector according to the present embodiment modulates lightemitted from a light source in accordance with image information andenlarges and projects the modulated light on a screen or any otherprojection surface. Further, the projector according to the presentembodiment includes input terminals and other components to be connectedto an external apparatus, and a cable cover that covers the inputterminals, cables connected to the input terminals, and other componentsis detachably provided.

Principal Configuration of Projector

FIG. 1 is an exterior view of a projector 1 according to the presentembodiment viewed from a projection surface side. FIG. 2 is an exteriorview of the projector 1 viewed from the side facing the projectionsurface. FIG. 3 is a diagrammatic view showing a schematic internalconfiguration of the projector 1. In the following sections, thefollowing definition is made for ease of description: the direction inwhich projection light is projected from the projector 1 is called a +Ydirection (frontward direction); the upward direction in the attitude ofthe projector 1 installed on a desktop or any other surface (standingattitude) is called a +Z direction (upward direction); and the rightwarddirection with respect to the projector 1 in the standing attitudeviewed from the side facing the projection surface is called a +Xdirection. The projector 1 is further capable of projection in theattitude of the projector installed on a ceiling or any other surface orin an upside-down attitude (hung attitude) instead of the standingattitude.

The projector 1 includes an exterior enclosure 2, which forms theexterior of the projector 1, a controller (not shown), an optical unit3, which includes a light source apparatus 31, an input operationsection 4, a plurality of input terminals 5, receivers 6F and 6B, and adetector 7, as shown in FIGS. 1 to 3. Although not shown, a cooler thatcools the optical unit 3 and other components, a power supply thatsupplies the controller and other components with electric power, andother components are disposed in the exterior enclosure 2.

The exterior enclosure 2 is a combination of a plurality of members madeof a synthetic resin and has a front surface portion 2F, an uppersurface portion 2U, a left side surface portion 2L, a right side surfaceportion 2R, a rear surface portion 2B, and a bottom surface portion 2T,as shown in FIG. 1.

The front surface portion 2F has the following portions formed therein:a projection opening 2 a, through which projection light from theoptical unit 3 passes; an opening 2 b for the receiver 6F; and anopening 2 c for the detector 7.

The projection opening 2 a is provided in a position shifted in therightward/leftward direction (±X direction) leftward (in −X direction)from the center, and the openings 2 b and 2 c are formed in positions onthe right (+X direction) side of the projection opening 2 a with theopening 2 b formed in a position above the opening 2 c.

The receiver 6F (see FIG. 3) is disposed in the opening 2 b, and theopening 2 b is closed by a filter member 21, which transmits infraredlight but blocks visible light.

The detector 7 (see FIG. 3) is disposed in the opening 2 c, and theopening 2 c is closed by a filter member 22, which has a hole formed atthe center, transmits infrared light, but blocks visible light. Thefilter member 21 and the filter member 22 may instead be integrated witheach other.

The upper surface portion 2U is a portion that from the upper side ofthe exterior enclosure 2 in the standing attitude of the projector 1.The upper surface portion 2U is provided with a swelling portion 20,which swells upward, a recessed portion 2 d, a plurality of openings inwhich a plurality of operation keys provided in the input operationsection 4 are disposed, and a lamp lid 23.

The swelling portion 20 swells in such a way that it covers part of acircumferential edge portion of a front-side lens 361, which forms aprojection lens 36 and will be described later, and connects with partof the circumferential edge of the projection opening 2 a. The swellingportion 20 has an inclined surface 20S, which faces rearward, and is soformed that the size in the frontward/rearward direction is smaller onthe upper end side than on the base end side, as shown in FIG. 2.

The recessed portion 2 d is formed in a portion behind the swellingportion 20, has a rectangular shape in a plan view, and has front, rear,right, and left sidewalls so inclined that the cross-sectional shape ofthe recessed portion 2 d decreases with distance toward the bottom, asshown in FIG. 2. The inclined surface on the side where the swellingportion 20 is present is formed along the inclined surface 20S of theswelling portion 20. An opening is provided in the inclined surface 20S,and the receiver 6B (see FIG. 3) is disposed in the opening. The openingin the inclined surface 20S is closed by a filter member 24, whichtransmits infrared light but blocks visible light.

An opening is formed through the bottom of the recessed portion 2 d, anda focus adjustment lever 364L, with which the projection lens 36, whichforms the optical unit 3 and will be described later, is provided, isexposed through the opening and disposed in the recessed portion 2 d.The lever 364L is so formed that the front end thereof does not extendoff the upper surface portion 2U.

The lamp lid 23 is provided in a position shifted toward the rearsurface side and the right-side end of the upper surface portion 2U andopened and closed when the light source apparatus 31 is exchanged.

An air intake port 2 i, through which outside air is introduced, isprovided in the left side surface portion 2L, as shown in FIG. 2. A dustfilter 25 is disposed inside the air intake port 2 i.

The right side surface portion 2R, which will not be illustrated indetail, is provided with an air exhaust port through which heated air inthe exterior enclosure 2 is exhausted out thereof.

The rear surface portion 2B is provided with a plurality of holes, andthe front end of each of the plurality of input terminals 5 is exposedthrough the corresponding one of the holes. A variety of types ofinformation outputted from an external image output apparatus (notshown) are delivered through the input terminals 5 to the controller.

The bottom surface portion 2T is provided with legs 26, which come intocontact with an installation surface when the projector 1 is installedon a table or any other object, and an attachment portion (not shown) towhich a fixture is attached when the projector 1 is hung from a ceilingor any other surface.

The legs 26 are formed of two legs 26B (see FIG. 2), which are disposedin positions in the vicinity of the right and left ends on the rearside, and a leg 26F (see FIG. 1), which is disposed in a central portionin the rightward/leftward direction on the front side.

The controller includes a CPU (central processing unit), a ROM (readonly memory), a RAM (random access memory), and other components,functions as a computer, and controls the action of the projector 1.

The optical unit 3 optically processes a light flux outputted from thelight source apparatus 31 and projects the processed light flux underthe control of the controller.

The optical unit 3 includes the light source apparatus 31, an opticalintegration illumination system 32, a color separation system 33, arelay system 34, an optical apparatus 35, the projection lens 36, and anoptical part enclosure 37, which arranges the members described above inpredetermined positions along the optical path, as shown in FIG. 3.

The light source apparatus 31 includes a discharge-type light source 311formed, for example, of an ultrahigh-pressure mercury lamp or a metalhalide lamp, a reflector 312, a parallelizing lens 313 as a lighttransmissive member, and a light source enclosure 314, whichaccommodates the members described above, as shown in FIG. 3.

In the light source apparatus 31, the reflector 312 reflects lightfluxes emitted from the light source 311, the parallelizing lens 313then aligns the directions of the reflected light fluxes with eachother, and the aligned light fluxes are directed toward the opticalintegration illumination system 32.

The optical integration illumination system 32 includes a first lensarray 321, a second lens array 322, a polarization conversion element323, and a superimposing lens 324, as shown in FIG. 3.

The first lens array 321 has a plurality of lenslets and divides thelight from the light source apparatus 31 into a plurality of sub-lightfluxes. The second lens array 322 and the superimposing lens 324 collectthe plurality of sub-light fluxes from the first lens array 321 andsuperimpose them on one another on each light modulator 351, which formsthe optical apparatus 35 and will be described later. The polarizationconversion element 323 includes a polarization separation film and awave plate and aligns the directions of the randomly polarized lightfluxes having exited out of the light source apparatus 31 with oneanother to form a polarized light flux having a predeterminedpolarization direction.

The color separation system 33 includes two dichroic mirrors 331 and 332and a reflection mirror 333 and has a function of separating the lightflux having exited out of the optical integration illumination system 32into three color light fluxes, red light (hereinafter referred to as “Rlight”), green light (hereinafter referred to as “G light”), and bluelight (hereinafter referred to as “B light”).

The relay system 34 includes a light-incident-side lens 341, a relaylens 343, and reflection mirrors 342 and 344 and has a function ofguiding the separated R light from the color separation system 33 to alight modulator 351 for R light. The optical unit 3 has a configurationin which the relay system 34 guides the R light, but the relay system 34does not necessarily guide the R light but may instead guide the Blight.

The optical apparatus 35 includes a light modulator 351 provided foreach of the color light fluxes (reference character 351R denotes lightmodulator for R light, reference character 351G denotes light modulatorfor G light, and reference character 351B denotes light modulator for Blight) and a cross dichroic prism 352 as a light combining opticalapparatus.

Each of the light modulators 351 includes a transmissive liquid crystalpanel, a light-incident-side polarizer disposed on the light incidentside of the liquid crystal panel, and a light-exiting-side polarizerdisposed on the light exiting side of the liquid crystal panel andmodulates the corresponding color light flux in accordance with imageinformation.

The cross dichroic prism 352 is formed by bonding four rectangularprisms and therefore has a roughly square shape in a plan view, and twodielectric multilayer films are formed along the interfaces between thebonded rectangular prisms. The cross dichroic prims 352, in which thedielectric multilayer films reflect the R light and the B lightmodulated by the light modulators 351R and 351B and transmit the G lightmodulated by the light modulator 351G, combines the three colormodulated light fluxes with one another.

The projection lens 36 is formed of a plurality of lenses arranged alongan optical axis 36Ax and enlarges and projects the light having exitedout of the cross dichroic prism 352 on the screen.

FIG. 4 is a perspective view showing the projection lens 36 and thereceiver 6B. FIG. 5 is a cross-sectional view of part of the projector 1in the vicinity of the swelling portion 20.

The projection lens 36 has the front-side lens 361, which is located onthe most downstream side (frontmost side) among the plurality of lenses,a guide barrel 362, a lens frame 363, a focus ring 364, and other parts,as shown in FIGS. 4 and 5.

The front-side lens 361 is a lens that contributes to a shorter focallength and a wider angle and has the largest diameter among theplurality of lenses. The front-side lens 361 has a truncated shape withno lower end portion, and light incident on the projection lens 36 iscaused to exit in an obliquely upward direction through the front-sidelens 361. The projector 1, which has a configuration in which theprojection lens 36 has the front-side lens 361, which contributes to ashorter focal length and a wider angle, can be installed in a positionin the vicinity of the projection surface or allows proximityprojection.

The guide barrel 362 has a holder 3621, which holds the circumferentialedge of the front-side lens 361, and accommodates a plurality of lenses(not shown) disposed on the light incident side of the front-side lens361.

The lens frame 363 is so formed that it covers the circumferential edgeof the holder 3621 and fixed to the holder 3621. The lens frame 363 inturn also covers a circumferential edge portion of the front-side lens361. The lens frame 363 has a front side part of which is exposedthrough the exterior enclosure 2 and a rear side to which the receiver6B is attached. That is, the swelling portion 20 covers part of thecircumferential edge portion of the front-side lens 361 (upper side ofcircumferential edge portion) via the holder 3621 and the lens frame363. A structure that allows attachment of the receiver 6B will bedescribed later in detail.

The focus ring 364 is formed in a tubular shape, and the lever 364L,which protrudes upward, is provided on the outer circumferential surfaceof the focus ring 364, as shown in FIG. 4. The lever 364L is disposed inthe recessed portion 2 d of the exterior enclosure 2, that is, behindthe swelling portion 20, as described above. When a user grasps thelever 364L and rotates the focus ring 364, a lens that contributes tofocus adjustment is so moved that focus adjustment is achieved. Zoomadjustment in the projector 1 according to the present embodiment iselectronically performed, that is, an image is enlarged and reduced byimage processing. The zoom adjustment is performed through operation ofthe input operation section 4 or the remote control for remote operationof the projector 1.

Referring back to FIG. 1, the input operation section 4 includes a firstoperation section 41, a second operation section 42, and a thirdoperation section 43.

The first operation section 41 has a mute switch key 41 a, whichswitches a display mode of a projected image, that is, stops orrestarting displaying the image. The mute switch key 41 a ispressed-down key and disposed on the right (+X direction) side of theswelling portion 20. Further, the mute switch key 41 a is located abovethe leg 26F or in a position where the projector 1 remains steady whenthe mute switch key 41 a is pressed down when operated.

The second operation section 42 is formed of a plurality of pressed-downoperation keys arranged in a portion on the left (−X direction) side ofthe lamp lid 23 as shown in FIG. 1. Specifically, the second operationsection 42 is formed of a power key 42 a, which switches the state ofthe power supply between ON and OFF, an input switch key 42 b, whichselects one of the plurality of input terminals 5, a menu key 42 c,which allows a menu setting image and other images to be displayed, fourcursor keys 42 d, which are used, for example, to select specify asetting item in the menu setting image and other images, a finalizingkey 42 e, which finalizes the selected setting item, a return key 42 f,which causes the current operation screen to return to a precedingoperation screen, and a help key 42 g, which allows a trouble handlingmethod to be shown.

The third operation section 43 has a trapezoidal distortion correctionkey 43 a, which is disposed behind the recessed portion 2 d and operatedin a slidable manner, as shown in FIG. 1.

The trapezoidal distortion correction key 43 a is operated to correct aprojected image so trapezoidally distorted that the right and left sidesof the image differ from each other in terms of length. The trapezoidaldistortion correction key 43 a is slidable in the rightward/leftwarddirection and provides a variable amount of correction according to theamount of slide. To correct a projected image so trapezoidally distortedthat the upper and lower sides of the image differ from each other interms of length, two of the four cursor keys 42 d are used.

The input terminals 5 include input terminals to which an image signal,a voice signal, and other signals can be inputted (for example,terminals that comply with HDMI (registered trademark) standard, videoterminals, and audio terminals) from an external apparatus (such ascomputer and video player).

Each of the receivers 6F and 6B receives an optical signal(infrared-light operation signal) issued from the remote control andoutputs an electric signal according to the received optical signal tothe controller.

The receiver 6F is disposed in the opening 2 b (see FIG. 1), asdescribed above, and receives an optical signal incident from the sidewhere light is projected through the projection lens 36, that is, anoptical signal incident from a position in front of the projector 1.

The receiver 6B is disposed in the swelling portion 20 (see FIG. 1) andso oriented that it receives an optical signal incident from the sideopposite to the side where light is projected through the projectionlens 36. That is, the receiver 6B receives an optical signal incidentfrom a position behind the projector 1.

The detector 7, although not illustrated in detail, includes an imager71 and a transmitter 72, as shown in FIG. 3.

The imager 71 includes, for example, a CCD (charge coupled device), aCMOS (complementary metal oxide semiconductor) device, or any otherimaging device (not shown) and captures an image of the projectionsurface as a subject. The imager 71 further detects infrared lightemitted from a pointing tool (electronic pen, for example) operated overthe projection surface and outputs detected information to thecontroller. The controller instructs projection of a superimposed imageformed of image information on which the trajectory of the pointing toolis superimposed on the projection surface based on a result of thedetection from the imager 71.

The transmitter 72 periodically issues an optical signal (infrared-lightsignal) to control the pointing tool operated over the projectionsurface. The pointing tool emits infrared light in synchronization withthe optical signal issued from the transmitter 72.

Configuration of Receiver

The configuration of the receiver 6B and the structure that allowsattachment of the receiver 6B will be described with reference to FIGS.4 and 5.

The receiver 6B includes a light receiving device 61 and a circuitsubstrate 62, on which the light receiving device 61 is mounted, and isattached to the lens frame 363, as described above.

The lens frame 363 has a standing wall 363 a, which is located behind(on the −Y-direction side of) the holder 3621, and a protrusion 363 b,which protrudes obliquely upward, is formed on the standing wall 363 a,as shown in FIG. 5.

The receiver 6B is fixed to the protrusion 363 b with a screw insertedinto a hole (not shown) provided in the circuit substrate 62. That is,the receiver 6B is fixed in a position behind (on the −Y-direction sideof) an upper circumferential edge portion of the front-side lens 361.

In the standing attitude of the projector 1, the receiver 6B is sodisposed that it receives an optical signal issued from an obliquelyupward position behind the projector 1. Specifically, the lightreceiving device 61 has a directional characteristic and is so disposedthat a central axis 6Ax of the area over which the light receivingdevice 61 has the directional characteristic, that is, the center of areception area over which the light receiving device 61 can receive anoptical signal separates away from the projector 1 by a greater distanceas the central axis 6Ax extends farther away from the swelling portion20. In other words, in the standing attitude of the projector 1, thereceiver 6B is so disposed that it receives an optical signal issuedfrom a position on and around the central axis 6Ax, the rear side ofwhich is inclined obliquely upward. The receiver 6B in the presentembodiment is so attached to the lens frame 363 that the angle of thecentral axis 6Ax with respect to the X-Y plane (attachment angle) isabout 30°.

Further, the light receiving device 61 has maximum reception sensitivityalong the central axis 6Ax, and the reception sensitivity lowers as theangle with respect to the central axis 6Ax increases. Specifically, thelight receiving device 61 on the present embodiment is formed of adevice having a directional angle θ of about 30°. The directional angleθ (see FIG. 5) used herein is an angle where the signal receivabledistance is one-half of that along the central axis 6Ax. The receiver 6Bis then so disposed that the area around the central axis 6Ax but withinthe directional angle θ (hereinafter referred to as “reception area Ra”)is located above the upper surface portion 2U. The lever 364L, whichdoes not extend off the upper surface portion 2U, is, of course, locatedin a position outside a predetermined area (reception area Ra).

The receiver 6B may instead be attached at an attachment angle differentfrom 30°. Further, the light receiving device 61 may instead be a devicehaving a directional angle θ different from 30°.

The receiver 6B is connected to the controller via a cable CA, as shownin FIG. 4. The receiver 6B, specifically, the light receiving device 61receives an optical signal transmitted from the remote control operatedby the user behind the projector 1 and outputs an electric signalaccording to the received optical signal to the controller. Thecontroller controls the projector 1 based on the electric signaloutputted from the receiver 6B.

FIG. 6 shows the projector 1 to which a cable cover 10 is attached andthe remote control RC located behind the projector 1.

The cable cover 10 is attached to the rear surface portion 2B (see FIG.2) of the projector 1 and covers the plurality of input terminals 5 (seeFIG. 2) and cables (not shown) connected to the input terminals 5.

The cable cover 10 has an upper surface portion 10U, a left side surfaceportion 10L, a right side surface portion 10R, and a bottom surfaceportion 10T, which are so formed that they follow the upper surfaceportion 2U, the left side surface portion 2L, the right side surfaceportion 2R, and the bottom surface portion 2T of the projector 1, and arear surface portion 10B and is formed in a box-like shape, as shown inFIG. 6. That is, the cable cover 10, when it is attached to theprojector 1, is integrated with the projector 1 (exterior enclosure 2)from the viewpoint of exterior appearance.

The swelling portion 20 protrudes from the upper surface portion 10Ueven in a state in which the cable cover 10 is attached to the projector1, and the reception area Ra (see FIG. 5), which is located above theupper surface portion 2U, is also located above the upper surfaceportion 10U. That is, even when the cable cover 10 is attached to theprojector 1, the user behind the projector 1 can remotely operate theprojector 1 by using the remote control RC, as in a case where the cablecover 10 is not attached to the projector 1.

The receiver 6F is configured in the same manner as the receiver 6B anddisposed and so oriented that it can receive an optical signal incidentfrom the remote control RC in a position in front of the projector 1.That is, the receiver 6F receives an optical signal issued from theremote control RC located, for example, in a position on the right orleft side of the projector 1 and a position in front thereof and thenreflected off the projection surface or any other object.

Further, either of the receivers 6F and 6B receives an optical signalissued from the transmitter 72 in the detector 7 in another projector 1and outputs an electric signal according to the received optical signalto the controller. For example, when a plurality of projectors 1 areused, and each of the projectors 1 is operated by using the pointingtool, each of the projectors 1 performs synchronization of a signal forcontrolling the pointing tool based on a reception result from thereceiver 6F or 6B. Each of the projectors 1 can thus project an image byusing the pointing tool in a stable manner without malfunction resultingfrom a wrong pointing tool.

Although not shown, the projector 1 can be installed on a ceiling or anyother surface via a fixture (not shown) in the hung attitude. In thehung attitude of the projector 1, the receiver 6B is so disposed that itreceives an optical signal issued from a position on and around thecentral axis 6Ax the rear side of which is inclined obliquely downward.

As described above, the projector 1 according to the present embodimentcan provide the following advantageous effects.

(1) The projector 1 has the receiver 6B disposed in the swelling portion20. The configuration allows the user behind the projector 1, even whenthe cable cover 10 is attached to the projector 1, to remotely controlthe projector 1 by using the remote control RC, as in the case where thecable cover 10 is not attached to the projector 1.

Further, the cable cover 10 does not have a special shape, such as ahole or a recess for optical signal reception, or is not provided with amember or any other portion that transmits an optical signal but is soformed that the cable cover 10 is attached to the projector 1 (exteriorenclosure 2) integrally therewith from the viewpoint of exteriorappearance. The exterior appearance of the projector 1 can therefore beimproved even when the cable cover 10 is attached thereto. Further,since the receiver 6B is disposed by using the swelling portion 20formed in correspondence with the front-side lens 361, the receiver 6Bcan be disposed without degradation in the exterior appearance of theprojector 1.

(2) Since the receiver 6B is so disposed that it is inclined asdescribed above, in the standing attitude in which the projector 1 isinstalled on a desktop or any other surface, the receiver 6B receives anoptical signal issued from an obliquely upward position behind theprojector 1 and positions therearound, whereas in the hung attitude, thereceiver 6B receives an optical signal issued from an obliquely downwardposition behind the projector and positions therearound. The receiver 6Bcan therefore reliably receive an optical signal issued when the remotecontrol RC is operated by a viewer of a projected image both in thestanding attitude and the hung attitude of the projector 1.

(3) Since the receiver 6B is attached to the lens frame 363, thereceiver 6B and the projection lens 36 can be manufactured integrallywith each other and then disposed in the exterior enclosure 2. The cableCA to be connected to the receiver 6B can therefore be readily wired orotherwise processed, whereby the projector 1 can be manufactured in asimplified manner.

(4) Since the lever 364L is located in a position outside the receptionarea Ra, the receiver 6B can reliably receive an optical signal from therear surface side even when focus adjustment is performed.

(5) Each of the receivers 6F and 6B has a function of receiving anoptical signal issued from the transmitter 72 in the detector 7 inanother projector 1 and outputting an electric signal according to thereceived optical signal to the controller. Therefore, even when aplurality of projectors 1 to each of which the cable cover 10 isattached are used by using the pointing tools, synchronization ofsignals for reliably controlling the pointing tools of the projectors 1can be reliably performed.

Variations

The embodiment described above may be changed as follows.

The projector 1 according to the embodiment described above includes thedetector 7, and a projector including no detector 7 may be provided.

The receiver 6B in the embodiment described above is configured toreceive an optical signal issued from the remote control RC or thetransmitter 72 in the detector 7. Instead, the receiver 6B may beconfigured to receive an optical signal issued from a device other thanthe remote control RC or the transmitter 72.

The receiver 6B in the embodiment described above is configured to beattached to the projection lens 36. Instead, the receiver 6B may beattached to the exterior enclosure 2, for example, a member thereof inwhich the filter member 24 is disposed.

In the embodiment described above, the receiver 6B is disposed in aposition behind (on the −Y-direction side of) the upper circumferentialedge portion of the front-side lens 361. Instead, the receiver 6B may bedisposed in a position above (on the +Z-direction side of) the uppercircumferential edge portion of the front-side lens 361.

The projector 1 according to the embodiment described above isconfigured to electronically perform zoom adjustment. Instead, a zoomadjustment mechanism that allows zoom adjustment may be accommodated inthe projection lens 36. In this case, the zoom adjustment mechanism maybe provided with a lever for zoom adjustment, and the lever may bedisposed in a position outside the reception area Ra.

The projector 1 according to the embodiment described above uses atransmissive liquid crystal panel as each of the light modulators butmay instead use a reflective liquid crystal panel. Still instead, amicromirror-type light modulator, such as a DMD (digital micromirrordevice), may be used as each of the modulators.

The light modulators in the embodiment described above employ what iscalled a three-panel method using three light modulators correspondingto the R light, the G light, and the B light but do not necessarilyemploy the three-panel method and may instead employ a single-panelmethod. The invention can even be applied to a projector including twolight modulators or four or more light modulators.

The light source apparatus 31 does not necessarily use thedischarge-type light source 311 and may be formed of a light sourcebased on a different method, a light emitting diode, a laser, or anyother solid-state light source.

The entire disclosure of Japanese Patent Application No. 2014-133751,filed Jun. 30, 2014 is expressly incorporated by reference herein.

What is claimed is:
 1. A projector comprising: a light source; a lightmodulator that modulates light emitted from the light source inaccordance with image information; a projection lens having a pluralityof lenses and projects the modulated light from the light modulator; areceiver that externally receives an optical signal and outputs anelectric signal according to the received optical signal; and anexterior enclosure that forms the exterior of the projector, wherein theprojection lens has a front-side lens disposed in a most downstreamposition in an optical path among the plurality of lenses and having adiameter larger than the diameters of the other lenses, the exteriorenclosure has an upper surface portion that faces upward in a standingattitude of the projector, the upper surface portion has a swellingportion that swells in such a way that the swelling portion covers partof a circumferential edge portion of the front-side lens, and thereceiver is disposed in the swelling portion and so oriented that thereceiver receives the optical signal incident from a side opposite to aside where the light is projected through the projection lens.
 2. Theprojector according to claim 1, wherein the receiver is so inclined thata central axis of an area over which the receiver has a directionalcharacteristic separates away from the projector by a greater distanceas the central axis extends farther away from the swelling portiontoward the opposite side.
 3. The projector according to claim 1, whereinthe receiver is attached to the projection lens.
 4. The projectoraccording to claim 1, wherein the projection lens is provided with alever located on the side opposite to the swelling portion and used forat least one of focus adjustment and zoom adjustment, and the lever islocated in a position outside a predetermined area containing a positionin the directional characteristic area of the receiver where receptionsensitivity is maximized.
 5. The projector according to claim 1, whereinthe receiver receives an optical signal issued from a remote controlused to remotely operate the projector.